Method for forming glass fibers



mm www 2 m7 u .mIxm Ww N wb Qw W. w s N Lm w wf. mm2. www NNN .NU wwF Dm s Q N M mw Sept. 6, 1966 Arroz/wy United States Patent() 3,271,122 METHOD FOR FORMING GLASS FIBERS Donald W. Denniston, Ross Township, Pa., and Clarence H. Helbing, Shelbyville, Ind., assignors to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Filed Nov. 25, 1959, Ser. No. 855,416 5 Claims. (Cl. 65-3) This invention relates to a method of `and `an apparatus for forming glass bers, and it has particular relation to a method and apparatus for forming continuous lament textile fibers under controlled conditions.

A process for forming continuous filament textile fibers is shown in U.S. Patent No. 2,133,238. In this process, a number of glass iilaments `are drawn from a molten supply of glass at a high .rate of speed, te., 5000 to 20,000 feet per minute. The mol-ten glass passes through orifices defined by hollow, cylindrical tips which extend downwardly from openings in the bottom of a bushing. The glass forms .cones suspended from the tips of the bushing and the individual lila-ments are drawn [from these cones. The individual filaments are grouped together into a strand as they pass over a guide and the strand is thereafter Iwound on -a rapidly rotating forming tube. The strand is rapidly traversed by suitable traversing means as it is lwound on the forming tube in order to have succeeding turns cross each other at a slight angle. This facilitates removal of the strand from the forming tube.

There is no twist in the strand as it is thus formed and ya Size is applied to the filaments prior to the Winding of the strand on the forming tube. The size contains a binder to give the strand integrity for Workability, i.e., twisting, .plying and weaving. lf the strand does not have proper integrity, fuzzing Aoccurs yduring these operations and eventually the operation -is interrupted due to the accumulation of the fuzz. The size also contains a lubricant rfor the rfilaments to prevent destruction of the strand by yabrasion of the individual lilaments against each other or against fiber handling equipment.

This process has been performed in the past on two operating levels because lit was 'felt that there needed to be substantial distances between the bushing and the guide and between the guide and the forming tube. The bush-ing and guide have been located on one floor and the forming tube on a door below. IIn Istarting up the process, the strand was passed by one person through an opening in the upper door to another person below who Wound Iit around the forming tube. It has been a desideratum of the art to move the bushing, guide and forming tube `closer together so that the process can be operated on one oor by a single operator.

Initial experiments on a one-floor process presented difculties in operating the process continuously without breakout of the strand. The exact causes of these difculties were not knot/vn. It was observed that the atmosphere in the area adjacent the forming tube contained a good deal of foreign material such .as dirt from the floor or particles of size thrown olf of the strand by the traverse 'guiding the strand onto the forming tube. The rotation of the forming tube and traverse caused this atmosphere to be extremely turbulent. In the one level process this atmosphere is much lcloser to the guide land the bushing and it is believed that this turbulent, dirty atmosphere might be responsible yfor preventing continuous operation. This may be caused by the foreign materials depositing on the guide or the bushing or the filaments themselves and interrupting the process to break out an individual filament. When a single fila-ment breaks, 'a fuzzy strand is produced and usual-ly the ber forming process is in- ICC terrupted. The turbulence of the atmosphere adjacent the forming tube may also .be a cause for the production of a lfuzzy strand or interruption of the process.

It is an object of the present invention to provide a method of making continuous textile bers which wil-1 operate efficiently on one level and can be oper-ated by one person. It is' another object of the present invention to provide a method of making glass liber strands free from fuzz and broken tilarnents. 'It is a further object of the invention to con-trol the atmosphere surrounding the process so as t-o permit most eicient Ioperation of the process.

These and other objects of the invention are accomplished by -controlling the atmosphere in `the forming area so that it moves generally in the direction of strand travel and particularly controlling the atmosphere adjacent the forming tube and traverse `to prevent it trom moving toward the guide and bushing. The strand is continuously enveloped with clean, conditioned air moving with the strand from the bushing to the `forming tube and beyond in the general direction of strand travel.

The `details of the invention are further described in conjunction with the drawing in which:

FIG. 1 is an elevation illustrating the glass liber process; and

FIG. 2 is a diagrammatic llow plan of the air conditioning system for the process.

ln FIG. l of the drawing there Lis shown a glass melting container or Iforehearth thereof containing a supply of molten glass 1K1 and having a bushing 12 attached to the bottom of the container. The bushing is provided through which the molten glass flows and forms in small cones 1'5 suspended from the tips. The orifices are aligned in 4 or more rows having -a great many tips in each rofw so that the total number olf tips is about 200 to 400. A smaller or greater number of rows or tips may be present in the bushing.

Glass filaments 116 'are pulled from the cones 15 of glass at a very high rate of speed, preferably 12,000 to 15,000 feet per minute, and Wound on a rapidly rotating forming tube 18 which may be approximately 6 to 7 inches in outside diameter and may rotate -at `approximately 5,000 to 10,000 revolutions per minute, preferably about 7,000 to 8,000 revolutions per minute depending upon the size of fiber being produced. The glass dilaments are grouped into a strand .19 as they pass over a guide 20 prior to their being wound on the tube 18. Usually a size lcontain-ing a liquid binder and lubricant ysuch as a combination .of starch and vegetable oil is applied to the individual `filaments of the strand as they pass over a. fel-t pad 211 mounted on the guide. The pad is saturated with the size. The size may also be applied to the lilaments just prior to the grouping of the fibers into the in Us. Patent No. 2,873,718.

As the strand 19 is wound on the tube 18, it is rapidly traversed in open wind along the length of the tube by means of a traverse 23. This traverse is shown in U.S. Patent No. 2,391,870 and it is composed of a shaft having a pair of complementary, conical, spirally disposed wire cams mounted on it. The .shaft is rotated at 1,000 to 2,500 revolutions per minute `and the cams push the strand back and forth across the face of the forming tube during the drawing operation.

A waste chute 22 made of sheet metal is located directly under the forming tube and traverse. This chute is mounted in the oor 24 of the forming room 25 and is open at the bottom and in line with an opening 26 in the floor of the forming room. In the basement 27 or room below the forming room 25 there is mounted on suitable supports 28 a metal hopper 29 for receiving waste materials from chute 22. These Waste materials are made up of scrap fibers and strand which are formed during the startup of the winding operation and of excess size which is not properly applied to the strand or which is thrown off of the strand as it is being wound on the forming tube. Also water from sprays used to clean the forming equipment passes through the chute 22.

During the traversing, the strand is physically maneuvered quite rapidly and some of the sizing solution is thrown off of the strand. The rotation of the traverse and the forming tube causes turbulence in the surrounding atmosphere and the sizing particles and any other foreign matter in this atmosphere are thrown outwardly. Prior to the present invention the sizing materials and foreign matter tend to be dispersed Within the forming room. In the single level operation described above, the proximity of the bushing and guide 4to the traverse and forming tube is such that they are inliuenced by this turbulent atmosphere and materials therein. The distance between the bushing guide is about 29 to 32 inches and the distance between the guide and the traverse is about 33 to 35 inches.

In order to control the `atmosphere in the forming room 25 two inlets 31 are located in the roof 32 of the forming room 25 and conditioned air is supplied to the yroom through each of these inlets. The inlets 31 are located in front of and behind the bushing and fore- -hearth in close proximity to them. The conditioned air Vpasses through the inlets under pressure so that it flows downwardly in the general direction of travel of the fibers and envelops the fibers. The air which is supplied to the forming room is conditioned as to temperature and humidity so that the forming room can be maintained at about 80 to 90 F. preferably 85 F. and 60 to 70, preferably 65, percent relative humidity. Usually there are a plurality of bushings and forming stations in a forming room. The forming room may be cornpletely closed or may be open at one or both ends. In any event, there is usually some leakage of air into the room other than that entering by way of inlets 31.

The humidity, temperature and `amount of the air supplied to the forming room may vary in order to ma'mtain the desired conditions in the forming room. For eX- ample, in a forming room of approximately 150 cubic feet per bushing, air may preferably be supplied for each bushing and forming station through two inlets 31 (5 by 22 inches in outlet dimensions) `at 54-60 F. and about 100 percent relative humidity. The air is supplied at a rate of about 300 to 700 cubic feet per minute per bushing. This air is supplied in such condition and at such -a flow rate as to create and maintain a definite downward fiow of conditioned air from the bushing to the forming tube and past the forming tube to and through the waste chute. The air ow through each waste chute, yallowing for about 10 percent leakage into the forming room, is about 330 to 770 cubic feet per minute. The velocity of the air passing through the chute is substantial so that a definite suction effect is created just above the chute in the area of the forming tube so as `to pull the air adjacent the forming tube into the chute.

The forming room 25 and basement 27 are designed so that 'air is withdrawn from the forming area through the opening 26 with which the chute 22 is aligned. Suitable means such as constant speed, variable pitch pulley fan 34 is provided in the waste hopper 29 to draw the air from the forming area through the opening 26 into and through the hopper 29 and into the basement area. The walls of the hopper 29 extend to the ceiling of the basement so that all of the air which passes -through the waste chute from the forming `room passes through the hopper. The hopper 29 is provided with a filter screen 35 in its side to permit the air to pass through the hopper into the basement. The fan 34 is mounted in tandem with the filter screen 35 so as to pull the air through the waste fibers and screen. The fibers collected in the hopper act as a filter to clean the air as it passes through `the hopper. This system pulls the atmosphere adjacent the winding tube and traverse down through the opening 26 into the basement 27 and does not allow it to circulate in the forming area 25. The air which passes to the basement may be recirculated to an air conditioning system 36 through an outlet 38 or exhausted to the atmosphere through an outlet 39 in the basement.

A diagrammatic view showing the flow plan of the air travel is shown in FIG. 2. The air is conditioned in conventional -air conditioner 36 and forced through lines 40 by constant speed variable pitch pulley fan 42 to the outlets 31 into the forming room 25. The conditioned air surrounds the fibers and passes downwardly in the direction of fiber travel past the traverse and forming tube, through the chute 22, hopper 29 and scrap fibers therein, screen 35 and into the basement. Most of the air flowing into the basement passes through the outlet 38 and back to the air conditioner through line 47. Some of it may pass out of the basement and be exhausted to the outside air through outlet 39. A preferred mode of operation is to have approximately 10 to 20 percent by weight exhausted to the atmosphere with each pass of air through the system. This amount of exhausted air is replenished in the system with new air brought into the air conditioner by line 50. The speed of fan 34 is regulated with respect to the speed of fan 42 so as to maintain as nearly as possible a constant air pressure in the forming room. The air passing through the openings 38 and 39 is controlled by conventional damper-s (not shown).

It has been found that the operation of the fiber forming process is superior when the lair adjacent the forming tube and traverse is drawn into the basement area and not allowed to circulate in the forming area. This superiority was evidenced by the production of strand free from fuzz and by an increase in the percentage of Icall downs, i.e., successful 8 to 15 minute drawing runs in a series of operating starts.

Although the present invention has been described with respect to certain embodiments thereof, it is not intended that such details be limitations upon the scope of the invention except insofar as set forth in the accompanying claims.

We claim:

1. A method of forming glass fibers which comprises drawing a plurality of fibers from a supply of molten glass, applying a coating to the fibers, advancing fibers to a collecting position, imparting rapid, sidewise oscillations to the fibers thereby removing portions of the coating from the fibers, surrounding the lfibers with an atmosphere moving in the direction of travel of the fibers and continuing movement of this `atmosphere in the same general direction beyond the collecting position thereby carrying the coating particles removed from the fibers away from the supply of molten glass.

2. A method of forming glass fibers which comprises establishing a fiber forming area, drawing a plurality of fibers from a supply of molten glass, applying a coating to the fibers, advancing the fibers to a collecting position, imparting rapid, sidewise oscillations to the fibers adjacent the collecting position thereby removing portions of the coating from the fibers, continuously fiowing conditioned air into the forming area near the supply, diowing the conditioned air around the fibers in the general direction of fiber travel to entrain the coating particles removed from the fibers, removing the conditioned air from the area by continuing its iliow away from the supply and balancing the rate of removal of air from the area fwith the rate of entry of air into the area so as to maintain a substantially constant pressure in the fiber forming area.

3. A method of forming glass tibers which comprises establishing a fiber forming area, drawing glass libers from a supply of molten glass, applying a size to the bers, grouping the fibers int-o -a strand, winding the strand on a forming tube, rapidly traversing the strand as it is 'wound on the forming tube thereby removing portions off the size, flowing conditioned `air into the arca adjacent the supply of glass, surrounding the bers with the air and moving the air in the general direction of fiber movement from the molten glass supply to the forming tube thereby entraining the lparticles of size and pulling the air adjacent the forming tube away from the tube so as to ycontinue the travel of the conditioned air and entrained size particles in a direction away from the supply of molten glass.

4. A met-hod of forming glass fbers Iwhich comprises, drawing glass `fibers from a supply of molten glass, applying a size to the bers, grouping the fibers into a strand, winding the strand on a lforming tube, imparting rapid sidewise Ioscillation to the strand as it is wound on the forming tube thereby removing portions of the size, introducing and flowing cooled cleaned air into the area adjacent the supply of glass, surrounding the l bers with said air and moving said introduced air in the general direction of iber movement from the molten glass supply to the forming tube, entraining particles of size Iint-o said air surrounding the lber, and pulling said introduced air adjacent the forming tube and containing entrained size away from the tube so as to continue the travel of substantially all of the introduced air together with the entrained particles of size .in a direction below the tube, away rfrom the supply of molten glass and through the rdoor and out of the area below the winding tube.

5. A method of forming glass fibers which comprises, drawing glass ibers from a supply of molten glass, applying a size to the bers, grouping the ibers into a strand, winding the str-and on a forming tube, imparting rapid sidewise oscillation t-o the strand as it is wound on the forming tube thereby removing portions of the size, introducing and owing cooled cleaned air into the area adjacent the supply of glass, surrounding the bers with said air and moving said introduced air in the general direction o't ber movement from the molten glass supply to the forming tube, entraining particles of size into said air surrounding the ber, pulling said introduced air adjacent the forming tube and containing entrained size away from the tube so as to continue the travel of substantially all of the introduced air together with entrained particles of size lin a direction 'below .the tube, away from the supply of molten glass and through the floor and out of the area `below the winding tube, cleaning and cooling at least a portion of the air so pulled, recycling said cooled air `to t-he area adjacent the supply of glass, and maintaining the air surrounding said fibers and strand at a relative humidity of about percent and a temperature of about F.-

References Cited by the Examiner UNITED STATES PATENTS 2,057,139 10/1936 Eaddy 242-355 2,386,158 10/1945 Collins. 2,391,870 1/1946 Beach. 2,540,415 2/ 1951 Altman. 2,767,519 10/ 1956 Bjorksten. 2,908,036 10/ 1959 Russell. 2,924,063 2/ 1960 Datwyler 57-56 DONALL H. SYLVESTER, Primary Examiner.

WILLIAM I STEPHENSON, MICHAEL V. BRINDISI, ARTHUR lP. KENT, JAMES S. BAILEY, MORRIS O. WO-LK, Examiners.

L. D. RUTLEDGE, G. R. MEYERS,

Assistant Examiners. 

1. A METHOD OF FORMING GLASS FIBERS WHICH COMPRISES DRAWING A PLURALITY OF FIBERS FROM A SUPPLY OF MOLTEN GLASS, APPLYING A COATING TO THE FIBERS, ADVANCING FIBERS TO A COLLECTING POSITION, IMPARTING RAPID, SIDEWISE OSCILLATONS TO THE FIBERS THEREBY REMOVING PORTIONS OF THE COATING FROM THE FIBERS, SURROUNDING THE FIBERS WITH AN ATMOSPHERE MOVING IN THE DIRECTION OF TRAVEL OF THE FIBERS AND CONTINUING MOVEMENT OF THIS ATMOSPHERE IN THE SAME GENERAL DIRECTION BEYOND THE COLLECTING POSITION THEREBY CARRYING THE COATING PARTICLE REMOVED FROM THE FIBERS AWAY FROM THE SUPPLY OF MOLTEN GLASS. 